ROCKFORD, MI — A senior Wolverine World Wide executive admits the global shoe company erred by leaving weathered leather scraps to litter the Rogue River banks in Rockford for years after demolition of the company's tannery complex.

"We shouldn't have done it," said Chris Hufnagel, senior vice president of corporate strategy at Rockford-based Wolverine. "And we are committed to cleaning it up."

Hufnagel said Wolverine is waiting for vegetation to recede this fall before cleaning up the litter, which is plainly visible near the Wolverine store at 235 N. Main Street.

After MLive published photos of the litter on Aug. 23, Hufnagel's reaction to learning the leather scraps remained on the riverbanks was to ask, "how they got there and why we didn't pick them up?"

"We have a responsibility," he said. "We live and work in this community. Our kids go to these schools. We fish in the Rogue River. We have to be good corporate citizens."

Rockford PFAS investigation at former Wolverine World Wide tannery

An old Hush Puppies brand shoe sole found along the Rogue River in Rockford on Thursday, Aug. 10, 2017. (Garret Ellison | MLive.com)

Hufnagel said he doesn't why they haven't been addressed until now, but indicated that leaving them was wrong.

"We should have dealt with that," he said.

"I don't know how or when it happened," he said. "I would say we benefit today by living in a society that has greater regulation and greater control. And I think the Earth is a better place for that. I think some things that were done however many years ago, in hindsight, we can sit here today with the benefit of time and hindsight and education and information and say, "man, that probably wasn't the right thing to do."

The removal work is part of larger environmental testing this fall around the former tannery, which was demolished in 2010.

Wolverine is sampling the site and river for per- and polyfluoroalkyl substances called PFAS, (also called perfluorinated chemicals, or PFCs).

The chemicals were in Scotchgard, which Wolverine used at the tannery to waterproof pigskin for Hush Puppies shoes.

The Concerned Citizens for Responsible Redevelopment in Rockford pushed the Michigan Department of Environmental Quality to take a closer look at PFAS concerns around the tannery and offsite waste disposal areas last year.

Richard Rediske, a scientist at Grand Valley State University's Annis Water Resources Institute, said that if the leather on the riverbank was treated with Scotchgard, regular stormwater runoff may be helping spread PFAS.

There is a fish consumption advisory for perfluoroctanesulfonic acid (PFOS), a PFAS compound that was the key ingredient in Scotchgard, upstream of the Rockford dam.

Rediske said investigation work needs to find the PFOS source, whether that be the leather debris, contaminated groundwater venting to the river, legacy contamination in the sediment behind the dam or a combination of each.

“The leather is everywhere," Rediske said. "It could have been treated with PFOS and could be a source of PFOS being found in fish in that area.”

Hufnagel met with MLive prior to a Sept. 12 meeting at Rockford High School to address Wolverine's contamination testing in Belmont, where private drinking water wells are polluted with Scotchgard chemicals from a tannery waste dump.

At the meeting, which lasted more than four hours and drew about 400 people, Hufnagal repeated many of the answers to questions posed by MLive earlier that day.